U.S. patent application number 15/616342 was filed with the patent office on 2017-12-07 for x-ray diagnostic apparatus and medical-information processing apparatus.
This patent application is currently assigned to Toshiba Medical Systems Corporation. The applicant listed for this patent is Toshiba Medical Systems Corporation. Invention is credited to Hiroyoshi KOBAYASHI, Katsunori KOJIMA, Akira MOCHIDUKl, Daisuke SATO, Masaharu SOYA, Kansei TAKAHASHI, Katsuo TAKAHASHI, Akio TETSUKA, Yuki TOTSUKA, Hisayuki UEHARA.
Application Number | 20170352518 15/616342 |
Document ID | / |
Family ID | 60482371 |
Filed Date | 2017-12-07 |
United States Patent
Application |
20170352518 |
Kind Code |
A1 |
TOTSUKA; Yuki ; et
al. |
December 7, 2017 |
X-RAY DIAGNOSTIC APPARATUS AND MEDICAL-INFORMATION PROCESSING
APPARATUS
Abstract
An X-ray diagnostic apparatus comprises an X-ray tube and
processing circuitry. The X-ray tube includes a rotary anode. The
processing circuitry is configured to derive an acquiring condition
from a fluoroscopic image, and start to increase, in accordance
with the acquiring condition derived, a rotating speed of the anode
from a low rotating speed to a high rotating speed before the X-ray
tube finishes emitting an X-ray to acquire the fluoroscopic
image.
Inventors: |
TOTSUKA; Yuki;
(Nasushiobara, JP) ; SOYA; Masaharu;
(Nasushiobara, JP) ; TAKAHASHI; Katsuo; (Yaita,
JP) ; TAKAHASHI; Kansei; (Nasushiobara, JP) ;
MOCHIDUKl; Akira; (Nasushiobara, JP) ; KOJIMA;
Katsunori; (Hadano, JP) ; SATO; Daisuke;
(Utsunomiya, JP) ; UEHARA; Hisayuki; (Otawara,
JP) ; KOBAYASHI; Hiroyoshi; (Nasushiobara, JP)
; TETSUKA; Akio; (Shioyagun, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Toshiba Medical Systems Corporation |
Otawara-shi |
|
JP |
|
|
Assignee: |
Toshiba Medical Systems
Corporation
Otawara-shi
JP
|
Family ID: |
60482371 |
Appl. No.: |
15/616342 |
Filed: |
June 7, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H05G 1/265 20130101;
H05G 1/66 20130101; A61B 6/06 20130101; A61B 6/465 20130101; A61B
6/486 20130101; A61B 6/487 20130101; A61B 6/40 20130101; A61B
6/4441 20130101; H05G 1/30 20130101; A61B 6/48 20130101; H01J 35/10
20130101; A61B 6/54 20130101; A61B 6/545 20130101; H01J 35/101
20130101; H05G 1/26 20130101; H01J 35/26 20130101; A61B 6/542
20130101 |
International
Class: |
H01J 35/10 20060101
H01J035/10; A61B 6/06 20060101 A61B006/06; A61B 6/00 20060101
A61B006/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 7, 2016 |
JP |
2016-113210 |
Claims
1. An X-ray diagnostic apparatus comprising: an X-ray tube
including a rotary anode; and processing circuitry configured to
derive an acquiring condition from a fluoroscopic image, and start
to increase, in accordance with the acquiring condition derived, a
rotating speed of the anode from a low rotating speed to a high
rotating speed before the X-ray tube finishes emitting an X-ray to
acquire the fluoroscopic image.
2. The X-ray diagnostic apparatus according to claim 1, wherein the
processing circuitry is configured to start image acquiring in an
interval from when the rotating speed of the anode reaches the high
rotating speed to when an elapsed time required to increase the low
rotating speed to the high rotating speed elapses after the X-ray
tube finishes emitting an X-ray to acquire the fluoroscopic
image.
3. The X-ray diagnostic apparatus according to claim 1, wherein the
processing circuitry is configured to start to increase the
rotating speed of the anode from the low rotating speed to the high
rotating speed if a variation in a statistic in brightness of
pixels of the fluoroscopic image satisfies a determination
condition.
4. The X-ray diagnostic apparatus according to claim 1, wherein the
processing circuitry is configured to start to increase the
rotating speed of the anode from the low rotating speed to the high
rotating speed if an operating mechanism is stopped and if a
variation in a statistic in brightness of pixels of the
fluoroscopic image satisfies a determination condition.
5. The X-ray diagnostic apparatus according to claim 4, wherein the
operating mechanism is a couch on which a subject is placed.
6. The X-ray diagnostic apparatus according to claim 4, wherein the
operating mechanism is a collimator that adjusts an irradiation
range of an X-ray.
7. The X-ray diagnostic apparatus according to claim 1, wherein the
processing circuitry is configured to start to increase the
rotating speed of the anode from the low rotating speed to the high
rotating speed if information indicating that a subject has stopped
breathing or information indicating that the subject has received a
command to stop breathing is received and if a variation in a
statistic in brightness of pixels of the fluoroscopic image
satisfies a determination condition.
8. The X-ray diagnostic apparatus according to claim 1, wherein the
processing circuitry is configured to start to increase the
rotating speed of the anode from the low rotating speed to the high
rotating speed if information indicating that a subject has stopped
moving or information indicating that the subject has received a
command to stop moving is received and if a variation in a
statistic in brightness of pixels of the fluoroscopic image
satisfies a determination condition.
9. The X-ray diagnostic apparatus according to claim 1, wherein the
processing circuitry is configured to start to increase the
rotating speed of the anode from the low rotating speed to the high
rotating speed if a user has performed a predetermined operation
and if a variation in a statistic in brightness of pixels of the
fluoroscopic image satisfies a determination condition.
10. The X-ray diagnostic apparatus according to claim 1, wherein
the processing circuitry is configured to start to increase the
rotating speed of the anode from the low rotating speed to the high
rotating speed if a predetermined time has elapsed after the X-ray
tube has started to emit an X-ray to acquire the fluoroscopic image
and if a variation in a statistic in brightness of pixels of the
fluoroscopic image satisfies a determination condition.
11. The X-ray diagnostic apparatus according to claim 1, wherein
the processing circuitry is configured to start to increase the
rotating speed of the anode from the low rotating speed to the high
rotating speed if a user satisfies a position condition and if a
variation in a statistic in brightness of pixels of the
fluoroscopic image satisfies a determination condition.
12. The X-ray diagnostic apparatus according to claim 3, wherein
the determination condition is a condition that the statistic falls
within a predetermined range during more than a predetermined
time.
13. The X-ray diagnostic apparatus according to claim 1, wherein
the processing circuitry is configured to perform a process to
determine a time when the rotating speed is started to increase
from the low rotating speed to the high rotating speed by using at
least one of following pieces of information as state information:
information that indicates a variation in a statistic in brightness
of pixels of the fluoroscopic image, information that indicates
whether an operating mechanism is stopped, information that
indicates whether a subject has stopped breathing, information that
indicates whether the subject has received a command to stop
breathing, information that indicates whether the subject has
stopped moving, information that indicates whether the subject has
received a command to stop moving, information that indicates
whether a user has performed a predetermined operation, information
that indicates a time that has elapsed after the X-ray tube has
started to emit an X-ray to acquire the fluoroscopic image, and
information that indicates a position of a user, the processing
circuitry performing the process, in accordance with a relationship
between the state information at a time when the rotating speed is
started to increase from the low rotating speed to the high
rotating speed and an evaluation of a time when the rotating speed
of the anode is started to increase from the low rotating speed to
the high rotating speed, to learn a weighting coefficient with
regard to each piece of the state information and determine the
time when the rotating speed is started to increase from the low
rotating speed to the high rotating speed based on the state
information input and the weighting coefficient, and start to
increase the rotating speed of the anode from the low rotating
speed to the high rotating speed at the time determined.
14. The X-ray diagnostic apparatus according to claim 1, wherein
the processing circuitry is configured to derive an irradiation
possible condition that may be implemented by using the rotating
speed of the anode, and acquire an acquisition image under the
irradiation possible condition if the acquiring condition does not
fall within the irradiation possible condition.
15. The X-ray diagnostic apparatus according to claim 1, wherein
the processing circuitry is configured to decrease the rotating
speed of the anode if the rotating speed of the anode is a rotating
speed at which the anode resonates.
16. An X-ray diagnostic apparatus comprising: an X-ray tube
including a rotary anode; and processing circuitry configured to
derive an acquiring condition from a fluoroscopic image and derive
an irradiation possible condition that may be implemented by using
a rotating speed of the anode, and acquire an acquisition image
under the irradiation possible condition if the acquiring condition
does not fall within the irradiation possible condition.
17. The X-ray diagnostic apparatus according to claim 16, wherein
the processing circuitry is configured to decrease the rotating
speed of the anode if the rotating speed of the anode is a rotating
speed at which the anode resonates.
18. A medical-information processing apparatus comprising
processing circuitry configured to acquire an acquiring condition
based on a fluoroscopic image, and calculate, in accordance with
the acquiring condition acquired, a time when a rotating speed of
the anode is started to increase from a low rotating speed to a
high rotating speed before an X-ray tube, including a rotary anode,
finishes emitting an X-ray to acquire the fluoroscopic image.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from Japanese Patent Application No. 2016-113210, filed on
Jun. 7, 2016; the entire contents of which are incorporated herein
by reference.
FIELD
[0002] Embodiments described herein relate generally to an X-ray
diagnostic apparatus and a medical-information processing
apparatus.
BACKGROUND
[0003] X-ray diagnostic apparatuses, including a rotary-anode type
X-ray tube, sometimes have three rotation modes, i.e., a stopped
state, a low rotating speed, and a high rotating speed. For
example, in the case of the low rotating speed, the X-ray
diagnostic apparatus may emit X-rays in a fluoroscopy mode and in
an acquiring mode with a low radiation dose. In the case of the
high rotating speed, the X-ray diagnostic apparatus may emit X-rays
in a fluoroscopy mode, in an acquiring mode with a low radiation
dose, and in an acquiring mode with a high radiation dose.
[0004] However, the X-ray diagnostic apparatus needs time to
increase the rotating speed of the anode from the stopped state or
the low rotating speed to the high rotating speed. Furthermore, if
the X-ray tube emits X-rays in such a state that the rotating speed
of the anode is insufficient, there is a possibility that the anode
is melted due to the heat that is caused by electron collision.
Therefore, conventional X-ray diagnostic apparatuses start to
acquire fluoroscopic images and acquisition images with delay.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a sequence diagram that illustrates an example of
the procedure before the conventional X-ray diagnostic apparatus
starts to acquire a fluoroscopic image or acquire an acquisition
image;
[0006] FIG. 2 is a diagram that illustrates an example of the case
where the conventional X-ray diagnostic apparatus increases the
rotating speed of the anode from the stopped state to the low
rotating speed and decreases from the low rotating speed to the
stopped state;
[0007] FIG. 3 is a diagram that illustrates an example of the case
where the conventional X-ray diagnostic apparatus increases the
rotating speed of the anode from the stopped state to the high
rotating speed and decreases from the high rotating speed to the
stopped state;
[0008] FIG. 4 is a block diagram that illustrates an example of the
configuration of an X-ray diagnostic apparatus according to a first
embodiment;
[0009] FIG. 5 is a diagram that illustrates an example of
high-voltage generation circuitry, an X-ray tube, and processing
circuitry according to the first embodiment;
[0010] FIG. 6 is a flowchart that illustrates an example of the
process that is performed by the X-ray diagnostic apparatus
according to the first embodiment;
[0011] FIG. 7 is a diagram that illustrates an example of the case
where the X-ray diagnostic apparatus according to the first
embodiment acquires a fluoroscopic image, increases the rotating
speed of the anode from the low rotating speed to the high rotating
speed, and acquires an acquisition image;
[0012] FIG. 8 is a diagram that illustrates an example of the case
where the conventional X-ray diagnostic apparatus acquires a
fluoroscopic image, increases the rotating speed of the anode from
the low rotating speed to the high rotating speed, and acquires an
acquisition image;
[0013] FIG. 9 is a flowchart that illustrates an example of the
process that is performed by the X-ray diagnostic apparatus
according to a second embodiment;
[0014] FIG. 10 is a diagram that illustrates an example of the case
where the X-ray diagnostic apparatus according to the second
embodiment acquires a fluoroscopic image and then increases the
rotating speed of the anode from the low rotating speed to the high
rotating speed while it acquires an acquisition image;
[0015] FIG. 11 is a diagram that illustrates an example of the case
where the X-ray diagnostic apparatus according to the second
embodiment increases the rotating speed of the anode from the
stopped state to the high rotating speed while it acquires an
acquisition image;
[0016] FIG. 12 is a diagram that illustrates an example of the case
where the conventional X-ray diagnostic apparatus increases the
rotating speed of the anode from the stopped state to the high
rotating speed and acquires an acquisition image; and
[0017] FIG. 13 is a diagram that illustrates an example of the case
where the X-ray diagnostic apparatus according to a third
embodiment decreases the rotating speed of the anode from the high
rotating speed to the stopped state while it applies a brake to the
anode.
DETAILED DESCRIPTION
[0018] An X-ray diagnostic apparatus according to embodiments
comprises an X-ray tube and processing circuitry. The X-ray tube
includes a rotary anode. The processing circuitry is configured to
derive an acquiring condition from a fluoroscopic image. And the
processing circuitry is configured to start to increase, in
accordance with the acquiring condition derived, a rotating speed
of the anode from a low rotating speed to a high rotating speed
before the X-ray tube finishes emitting an X-ray to acquire the
fluoroscopic image.
[0019] With reference to the drawings, an explanation is given
below of the X-ray diagnostic apparatus according to an embodiment.
Furthermore, in the following embodiment, duplicated explanation is
appropriately omitted.
[0020] First, in order to make it easy to understand processes of
the X-ray diagnostic apparatus according to the first embodiment,
with reference to FIGS. 1, 2, and 3, an explanation is given of how
a conventional X-ray diagnostic apparatus increases the rotating
speed of the anode of the X-ray tube from the stopped state to the
low rotating speed or the high rotating speed and decreases the
rotating speed of the anode from the low rotating speed or the high
rotating speed to the stopped state. FIG. 1 is a sequence diagram
that illustrates an example of the procedure before the
conventional X-ray diagnostic apparatus starts to acquire a
fluoroscopic image or acquire an acquisition image. FIG. 2 is a
diagram that illustrates an example of the case where the
conventional X-ray diagnostic apparatus increases the rotating
speed of the anode from the stopped state to the low rotating speed
and decreases from the low rotating speed to the stopped state.
FIG. 3 is a diagram that illustrates an example of the case where
the conventional X-ray diagnostic apparatus increases the rotating
speed of the anode from the stopped state to the high rotating
speed and decreases from the high rotating speed to the stopped
state.
[0021] As illustrated in FIG. 1, the conventional X-ray diagnostic
apparatus includes input circuitry, the X-ray tube, high-voltage
generation circuitry, and anode drive circuitry. For example, in
accordance with a user's operation, the input circuitry transmits a
command to the high-voltage generation circuitry and the anode
drive circuitry so as to start to prepare for X-ray emission. In
accordance with the command, the high-voltage generation circuitry
starts to apply heat to the cathode of the X-ray tube. If heating
of the cathode is completed, the X-ray tube transmits the message
indicating it to the high-voltage generation circuitry. In
accordance with the command, the anode drive circuitry starts to
increase the rotating speed of the anode from the stopped state to
the low rotating speed or the high rotating speed. If the rotating
speed of the anode reaches the low rotating speed or the high
rotating speed, the anode drive circuitry transmits the message
indicating it to the high-voltage generation circuitry. For
example, in accordance with a user's operation, the input circuitry
transmits a command to the high-voltage generation circuitry so as
to start to emit X-rays. In accordance with the command, the
high-voltage generation circuitry applies a high voltage to the
X-ray tube so as to start to emit X-rays.
[0022] When a fluoroscopic image of the subject is acquired, the
conventional X-ray diagnostic apparatus sets the rotating speed of
the anode of the X-ray tube to the low rotating speed. The low
rotating speed is for example 60 Hz. Furthermore, when an
acquisition image of the subject is acquired, the conventional
X-ray diagnostic apparatus sets the rotating speed of the anode of
the X-ray tube to the high rotating speed. The high rotating speed
is for example 180 Hz. Moreover, the rotating speed of the anode in
the stopped state is 0 Hz.
[0023] Here, fluoroscopic images are X-ray images that are acquired
in chronological order when a detector detects X-rays that are
emitted from the X-ray tube. For example, fluoroscopic images are
used for deriving an acquiring condition, observing a subject in
real time, or the like. Fluoroscopic images often do enough with
low image quality as compared with acquisition images; therefore,
they are usually acquired by using low-dose X-rays compared to
X-rays that are used for acquiring acquisition images.
[0024] Furthermore, acquisition images are X-ray images that are
acquired when a detector detects X-rays that are emitted from the
X-ray tube, and for example they are used for diagnostic imaging.
Specifically, a user, such as a doctor, views acquisition images to
find areas of lesion of a subject or consider treatment planning
for areas of lesion. Therefore, acquisition images are usually
acquired with high image quality by using high-dose X-rays as
compared to X-rays that are used for acquiring fluoroscopic
images.
[0025] As illustrated in FIG. 2, the anode drive circuitry needs at
least a time t(S) to increase the rotating speed of the anode from
the stopped state to the low rotating speed. The time t(S) is for
example about 1 second. Furthermore, as illustrated in FIG. 3, the
anode drive circuitry needs at least a time T(S) to increase the
rotating speed of the anode from the stopped state to the high
rotating speed. The time T(S) is for example about 2 seconds. It is
difficult for the conventional X-ray diagnostic apparatus to
conduct acquiring of fluoroscopic images and acquiring of
acquisition images during the time t(S) and the time T(S).
Therefore, with the conventional X-ray diagnostic apparatus, the
start of acquiring of fluoroscopic images and acquiring of
acquisition images is delayed.
[0026] As illustrated in FIG. 2, to decrease the rotating speed of
the anode from the low rotating speed to the stopped state, the
anode drive circuitry applies a brake to the rotation of the anode
during at least a time t(E). The time t(E) is for example about 3
seconds. Furthermore, as illustrated in FIG. 3, to decrease the
rotating speed of the anode from the high rotating speed to the
stopped state, the anode drive circuitry applies a brake to the
rotation of the anode during at least a time T(E). The time T(E) is
for example about 3 seconds.
[0027] Specifically, although it is only necessary to applies a
brake to the anode in the case of the rotating speed of the anode
at which the anode resonates, as indicated by an area A in FIG. 3,
the anode drive circuitry applies a brake to the anode during the
time t(E) or the time T(E) all the time. Therefore, the
conventional X-ray diagnostic apparatus causes the coil, which
applies a brake to the anode, and the anode drive circuitry to
generate heat more than necessary, and there is an increase in the
energy that is needed to applies a brake to the anode. Furthermore,
even if an acquisition image of a subject is acquired and then
immediately an acquisition image of the next subject is acquired,
the conventional X-ray diagnostic apparatus uniformly decreases the
rotating speed of the anode to the stopped state. Therefore, the
conventional X-ray diagnostic apparatus spends unnecessary time in
increasing the rotating speed of the anode to the low rotating
speed or the high rotating speed again. Furthermore, it is
difficult for the conventional X-ray diagnostic apparatus to
acquire acquisition images while the anode drive circuitry applies
a brake to the rotation of the anode. Furthermore, if the anode is
continuously rotated at the low rotating speed or the high rotating
speed on a constant basis, the shaft bearing, which supports the
anode, is degraded and the operating life of the X-ray tube is
reduced.
[0028] Next, with reference to FIG. 4, the configuration of an
X-ray diagnostic apparatus 1 according to the first embodiment is
explained. FIG. 4 is a block diagram that illustrates an example of
the configuration of the X-ray diagnostic apparatus according to
the first embodiment. As illustrated in FIG. 4, the X-ray
diagnostic apparatus 1 includes an image acquisition apparatus 10
and a console 20. Furthermore, the configuration of the X-ray
diagnostic apparatus 1 is not limited to the configuration
described below.
[0029] The image acquisition apparatus 10 includes high-voltage
generation circuitry 11, collimator adjustment circuitry 12, a
couch 13, an X-ray tube 14, a collimator 15, anode drive circuitry
16, an X-ray detector 17, a C arm 18, and drive circuitry 19.
[0030] The high-voltage generation circuitry 11 feeds a high
voltage for the X-ray tube 14 to generate X-rays. The details of
the high-voltage generation circuitry 11 are described later. The
collimator adjustment circuitry 12 controls the collimator 15 to
adjust the irradiation range of X-rays that are generated by the
X-ray tube 14. The high-voltage generation circuitry 11 and the
collimator adjustment circuitry 12 read and execute programs that
are stored in memory circuitry 25, which is described later, to
implement the functions.
[0031] The couch 13 is a bed that includes a tabletop, on which a
subject P is placed. The X-ray tube 14 uses the high voltage, fed
by the high-voltage generation circuitry 11, to generate X-rays
that are emitted to the subject P. The details of the X-ray tube 14
are described later.
[0032] The collimator 15 adjusts the irradiation range of X-rays
that are generated by the X-ray tube 14. The collimator 15 is
provided between the X-ray tube 14 and the X-ray detector 17. The
collimator 15 includes for example four slidable aperture blades.
The collimator 15 slides the aperture blades to adjust the range
within which the X-rays, generated by the X-ray tube 14, are
emitted. In accordance with a command that is transmitted by a
rotating-speed control function 263, which is described later, the
anode drive circuitry 16 controls the rotating speed of an anode
142, which is described later, and applies a brake to the rotation
of the anode 142. The anode drive circuitry 16 controls the current
that flows through the coil, which generates the rotating magnetic
field, to control the rotating speed of the anode 142 and apply a
brake to the rotation of the anode 142.
[0033] The X-ray detector 17 detects X-rays that are emitted by the
X-ray tube 14. The X-ray detector 17 is for example a Flat Panel
Detector (FPD). The X-ray detector 17 includes detecting elements
that are arranged in a matrix. The detecting element converts
X-rays, emitted by the X-ray tube 14, into electric signals and
stores them. The stored electric signals are transmitted to
generation circuitry 23 that is described later.
[0034] The X-ray tube 14 and the collimator 15 are opposed to the
X-ray detector 17 with the subject P interposed therebetween, and
they are held by the C arm 18.
[0035] The drive circuitry 19 moves the C arm 18. The drive
circuitry 19 changes the Source Image receptor Distance (SID),
which is the distance between the X-ray tube 14 and the X-ray
detector 17. Furthermore, the drive circuitry 19 is capable of
rotating the X-ray detector 17, held by the C arm 18, within the
plane in which the detecting elements are arranged in a matrix.
Moreover, the drive circuitry 19 moves the tabletop, on which the
subject P is placed, in a horizontal direction and in a vertical
direction. The drive circuitry 19 reads and executes programs that
are stored in the memory circuitry 25, which is described later,
and implements the functions.
[0036] The console 20 includes input circuitry 21, a display 22,
the generation circuitry 23, image memory circuitry 24, the memory
circuitry 25, and processing circuitry 26.
[0037] The input circuitry 21 is used by a user who inputs commands
or settings. The input circuitry 21 is included in for example a
mouse or a keyboard. The input circuitry 21 transfers commands or
settings, input by the user, to the processing circuitry 26. The
input circuitry 21 is implemented by for example a processor.
[0038] The display 22 is a monitor that is viewed by the user. The
display 22 is for example a liquid crystal display. For example,
the display 22 receives commands to display fluoroscopic images,
acquisition images, or the Graphical User Interface (GUI) from the
processing circuitry 26. This allows the display 22 to present
fluoroscopic images, acquisition images, and the GUI. The GUI is
used when the user inputs commands or settings.
[0039] The generation circuitry 23 generates fluoroscopic images or
acquisition images on the basis of electric signals that are output
by each of the detecting elements. The generation circuitry 23
reads and executes programs that are stored in the memory circuitry
25, which is described later, to implement the functions. Here, the
generation circuitry 23 is implemented by for example a
processor.
[0040] The image memory circuitry 24 stores fluoroscopic images or
acquisition images that are generated by the generation circuitry
23. The memory circuitry 25 stores programs for the high-voltage
generation circuitry 11, the collimator adjustment circuitry 12,
and the drive circuitry 19 to implement the above-described
functions. The memory circuitry 25 stores programs for the
generation circuitry 23 and the processing circuitry 26 to
implement each function that is described later. The image memory
circuitry 24 and the memory circuitry 25 include a storage medium,
from which the stored information may be read by a computer. The
storage medium is for example a hard disk.
[0041] The processing circuitry 26 includes a monitoring function
261, a derivation function 262, the rotating-speed control function
263, an image-acquiring control function 264, and a control
function 265. The processing circuitry 26 is implemented by for
example a processor.
[0042] The monitoring function 261 monitors the rotating speed of
the anode 142 of the X-ray tube 14. The derivation function 262
derives an acquiring condition from a fluoroscopic image. In
accordance with the derived acquiring condition, the rotating-speed
control function 263 starts to increase the rotating speed of the
anode 142 from the low rotating speed to the high rotating speed
before the X-ray tube 14 finishes emitting X-rays to acquire
fluoroscopic images. The low rotating speed is a rotating speed of
the anode 142 to acquire fluoroscopic images. The high rotating
speed is a rotating speed of the anode 142 to acquire fluoroscopic
images or acquisition images. That is, the high rotating speed is a
rotating speed higher than the low rotating speed. The details of
the monitoring function 261, the derivation function 262, and the
rotating-speed control function 263 are described later.
[0043] The image-acquiring control function 264 is a function to
acquire fluoroscopic images or acquisition images by controlling
the high-voltage generation circuitry 11, the collimator adjustment
circuitry 12, the anode drive circuitry 16, the drive circuitry 19,
and the generation circuitry 23. Specifically, the image-acquiring
control function 264 performs the following control. First, the
image-acquiring control function 264 controls the drive circuitry
19 to move the X-ray tube 14, the collimator 15, and the X-ray
detector 17 to positions that are suitable for acquiring
fluoroscopic images or acquisition images. Next, the
image-acquiring control function 264 controls the high-voltage
generation circuitry 11, the collimator adjustment circuitry 12,
and the anode drive circuitry 16 so as to emit X-rays to the
subject P. Then, the image-acquiring control function 264 controls
the generation circuitry 23 so as to generate fluoroscopic images
or acquisition images. Furthermore, if a moving image is acquired,
the image-acquiring control function 264 controls the generation
circuitry 23 so as to perform the above-described process on each
frame of the moving image.
[0044] The image-acquiring control function 264 starts image
acquiring in the interval from when the rotating speed of the anode
142 reaches the high rotating speed to when an elapsed time
elapses. The elapsed time is time required to increase the low
rotating speed to the high rotating speed after the X-ray tube 14
finishes emitting X-rays to acquire the fluoroscopic image. The
details of the image-acquiring control function 264 are described
later.
[0045] The control function 265 has the function to operate each
component of the image acquisition apparatus 10 and the console 20
in accordance with a purpose at appropriate timing as well as other
functions.
[0046] Next, with reference to FIG. 5, an explanation is given of
the high-voltage generation circuitry 11, the X-ray tube 14, and
the processing circuitry 26, included in the X-ray diagnostic
apparatus 1. FIG. 5 is a diagram that illustrates an example of the
high-voltage generation circuitry 11, the X-ray tube 14, and the
processing circuitry 26 according to the first embodiment.
[0047] As illustrated in FIG. 5, the X-ray diagnostic apparatus 1
includes the high-voltage generation circuitry 11, the X-ray tube
14, and the processing circuitry 26.
[0048] The high-voltage generation circuitry 11 includes
tube-current detection circuitry 111, tube-voltage control
circuitry 112, grid-potential control circuitry 113, and
cathode-current control circuitry 114.
[0049] The tube-current detection circuitry 111 detects the tube
current that flows between a cathode 141, which is described later,
and the anode 142. Specifically, it acquires the time-series data
on the tube current that flows between the cathode 141 and the
anode 142. The tube-voltage control circuitry 112 controls the tube
voltage that is applied between the cathode 141 and the anode 142.
The grid-potential control circuitry 113 controls the electric
potential of a grid 143 that is described later. The
cathode-current control circuitry 114 controls the current that
flows through the cathode 141 that is described later. Here, the
tube-current detection circuitry 111, the tube-voltage control
circuitry 112, the grid-potential control circuitry 113, and the
cathode-current control circuitry 114 are implemented by for
example a processor.
[0050] The X-ray tube 14 includes the cathode 141, the anode 142,
the grid 143, a glass bulb 144, and a rotating-speed monitoring
device 145.
[0051] The cathode 141 emits electrons. Specifically, the cathode
141 is heated due to the currents that are supplied by the
cathode-current control circuitry 114, which is described later, so
as to emit thermal electrons. The anode 142 generates X-rays when
it receives electrons that are emitted by the cathode 141. The
anode 142 is rotated due to the rotating magnetic field that is
generated by the coil. The grid 143 is a structure that is provided
on the circumference of the cathode 141. The grid 143 adjusts the
potential gradient around the cathode 141 and switches on/off
X-rays that are generated by the anode 142. The glass bulb 144 is a
glass container that houses the cathode 141, the anode 142, and the
grid 143.
[0052] The rotating-speed monitoring device 145 monitors the
rotating speed of the anode 142. The method for monitoring the
rotating speed of the anode 142 by the rotating-speed monitoring
device 145 is not particularly limited. The rotating-speed
monitoring device 145 uses for example lasers or infrared rays to
measure the rotating speed of the anode 142 without being in
contact with the anode 142. Alternatively, the rotating-speed
monitoring device 145 measures oscillations of the anode 142 to
measure the rotating speed of the anode 142. Alternatively, the
rotating-speed monitoring device 145 calculates the rotating speed
of the anode 142 by using the electric power that is supplied by
the anode drive circuitry 16 to the X-ray tube 14 or its set value.
The rotating-speed monitoring device 145 transmits the monitored
rotating speed of the anode 142 to the processing circuitry 26,
which is described later, as appropriate.
[0053] Next, with reference to FIGS. 6, 7, and 8, the process
performed by the X-ray diagnostic apparatus 1 according to the
first embodiment is explained. FIG. 6 is a flowchart that
illustrates an example of the process that is performed by the
X-ray diagnostic apparatus 1 according to the first embodiment.
FIG. 7 is a diagram that illustrates an example of the case where
the X-ray diagnostic apparatus 1 according to the first embodiment
acquires a fluoroscopic image, increases the rotating speed of the
anode from the low rotating speed to the high rotating speed, and
acquires an acquisition image. FIG. 8 is a diagram that illustrates
an example of the case where the conventional X-ray diagnostic
apparatus acquires a fluoroscopic image, increases the rotating
speed of the anode from the low rotating speed to the high rotating
speed, and acquires an acquisition image.
[0054] While the X-ray diagnostic apparatus 1 is in operation, the
processing circuitry 26 reads the program, which corresponds to the
monitoring function 261, from the memory circuitry 25 and executes
it to receive the rotating speed of the anode 142 from the
rotating-speed monitoring device 145.
[0055] As illustrated in FIG. 6, the processing circuitry 26 reads
the program, which corresponds to the control function 265, from
the memory circuitry 25 and executes it to determine whether it has
received a command to start to acquire a fluoroscopic image (Step
S11). If a command for starting to acquire a fluoroscopic image has
been received (Yes at Step S11), the processing circuitry 26
proceeds to the operation at Step S12. If a command for starting to
acquire a fluoroscopic image has not been received (No at Step
S11), the processing circuitry 26 stands by until a command for
starting to acquire a fluoroscopic image is received. A command for
starting to acquire a fluoroscopic image is input by for example a
user who uses the input circuitry 21.
[0056] As illustrated in FIG. 6, the processing circuitry 26 reads
the program, which corresponds to the image-acquiring control
function 264, and the program, which corresponds to the derivation
function 262, from the memory circuitry 25 and executes them to
start to acquire a fluoroscopic image and derive an acquiring
condition (Step S12). For example, as illustrated in FIG. 7, the
X-ray diagnostic apparatus 1 derives an acquiring condition from a
fluoroscopic image while it conducts pulsed fluoroscopy on the
subject P. Alternatively, the X-ray diagnostic apparatus 1 derives
an acquiring condition from a fluoroscopic image while it conducts
continuous fluoroscopy on the subject P. Here, the acquiring
condition is a condition under which the X-ray diagnostic apparatus
1 acquires acquisition images of the subject P. The acquiring
condition is, for example, the rotating speed of the anode 142, the
tube current, the tube voltage, the current that flows through the
cathode 141, the electric potential of the grid 143, the positions
of the aperture blades of the collimator 15, the position of the
tabletop of the couch 13, or the arrangement of the C arm 18.
Furthermore, the vertical axis in the lower diagram of FIG. 7
indicates the X-ray condition. Here, the X-ray condition means the
tube voltage, the tube current, and the time during which X-rays
are emitted. Furthermore, the same holds for the vertical axis in
the lower diagram of FIGS. 8, 10, 11, and 12.
[0057] As illustrated in FIG. 6, the processing circuitry 26 reads
the program, which corresponds to the rotating-speed control
function 263, from the memory circuitry 25 and executes it to
determine whether derivation of the acquiring condition is finished
(Step S13). If derivation of the acquiring condition is finished
(Yes at Step S13), the processing circuitry 26 proceeds to the
operation at Step S14. If derivation of the acquiring condition is
not finished (No at Step S13), the processing circuitry 26 stands
by until derivation of the acquiring condition is finished. For
example, the rotating-speed control function 263 determines that
the derivation function 262 has finished deriving the acquiring
condition by using the following method.
[0058] If variations in the statistic in the brightness of pixels
of a fluoroscopic image satisfy a determination condition, the
rotating-speed control function 263 determines that the derivation
function 262 has finished deriving the acquiring condition. Here,
for example, the determination condition is a condition such that
the statistic falls within a predetermined range during more than a
predetermined time. Here, the predetermined time and the
predetermined range are the time and the range that are set before
acquiring of fluoroscopic images of the subject P is started. The
time and the range may be conditions that are set by a user, or
they may be preset fixed conditions. Furthermore, the statistic is
for example an average, variance, standard deviation, maximal
value, minimum value, middle value, or mode value. Furthermore, the
statistic, mentioned here, may be for example the amount that is
defined by the user of the X-ray diagnostic apparatus 1 as
needed.
[0059] The rotating-speed control function 263 may determine that
the derivation function 262 has finished deriving the acquiring
condition if an operating mechanism is stopped and variations in
the statistic in the brightness of pixels of a fluoroscopic image
satisfy the determination condition. Here, the operating mechanism
is a component that is included in the components of the image
acquisition apparatus 10 and that makes movement or deformation in
accordance with the acquiring condition preparatory to image
acquiring. Examples of the operating mechanism include the couch
13, on which the subject P is placed, the collimator 15 that
adjusts the irradiation range of X-rays, or the C arm 18.
Specifically, as the couch 13 moves the tabletop to adjust the
position of the subject P preparatory to image acquiring, it is
included in the operating mechanism. Furthermore, as the collimator
15 slides the aperture blades to control the X-rays irradiation
range preparatory to image acquiring, it is included in the
operating mechanism. Moreover, as the C arm 18 moves the X-ray tube
14, the collimator 15, or the X-ray detector 17 to control the
irradiation angle of X-rays, or the like, it is included in the
operating mechanism. Conversely, for example, although the anode
142 is a component that rotates and moves in accordance with an
acquiring condition, it does not rotate or move preparatory to
image acquiring; therefore, it is not included in the operating
mechanism.
[0060] For example, if the couch 13, on which the subject P is
placed, is stopped, the rotating-speed control function 263
determines that the derivation function 262 has finished deriving
the acquiring condition. Furthermore, for example, if the
collimator 15 is stopped, the rotating-speed control function 263
determines that the derivation function 262 has finished deriving
the acquiring condition. This is because, if the couch 13 or the
collimator 15 is stopped, it may be determined that the X-ray
diagnostic apparatus 1 is making preparations to acquire
acquisition images under the acquiring condition that is derived at
Step S12 except for the rotating speed of the anode 142 and
associated conditions. However, the rotating-speed control function
263 does not always determine whether the derivation function 262
has finished deriving the acquiring condition only on the basis of
movements of the couch 13 or the collimator 15. Therefore, it is
preferable that the rotating-speed control function 263 uses these
methods in combination with the method of using the statistic in
the brightness of pixels of a fluoroscopic image or other
methods.
[0061] If the information indicating that the subject P has stopped
breathing or the information indicating that the subject P has
received a command to stop breathing is received, the
rotating-speed control function 263 may determine that the
derivation function 262 has finished deriving the acquiring
condition. Furthermore, if the information indicating that the
subject P has stopped moving or the information indicating that the
subject P has received a command to stop moving is received, the
rotating-speed control function 263 may determine that the
derivation function 262 has finished deriving the acquiring
condition. This is because, if the processing circuitry 26 has
received the information, it may be determined that the X-ray
diagnostic apparatus 1 is making preparations to acquire
acquisition images under the acquiring condition that is derived at
Step S12 except for the rotating speed of the anode 142 and
associated conditions. However, the rotating-speed control function
263 does not always determine whether the derivation function 262
has finished deriving the acquiring condition only on the basis of
whether the processing circuitry 26 has received the information.
Therefore, it is preferable that the rotating-speed control
function 263 uses these methods in combination with the method of
using the statistic in the brightness of pixels of a fluoroscopic
image or other methods. For example, the rotating-speed control
function 263 determines that the derivation function 262 has
finished deriving the acquiring condition if the information
indicating that the subject P has stopped breathing or the
information indicating that the subject P has received a command to
stop breathing is received and if variations in the statistic in
the brightness of pixels of a fluoroscopic image satisfy the
determination condition. Furthermore, for example, the
rotating-speed control function 263 determines that the derivation
function 262 has finished deriving the acquiring condition if the
information indicating that the subject P has stopped moving or the
information indicating that the subject P has received a command to
stop moving is received and if variations in the statistic in the
brightness of pixels of a fluoroscopic image satisfy the
determination condition.
[0062] The rotating-speed control function 263 may determine that
the derivation function 262 has finished deriving the acquiring
condition if the user has performed a predetermined operation. The
predetermined operation, mentioned here, is an operation that is
frequently performed when an acquisition image of a specific site
of the subject P is acquired by using a specific method. This is
because, if such an operation is performed, it may be determined
that the X-ray diagnostic apparatus 1 is making preparations to
acquire acquisition images under the acquiring condition that is
derived at Step S12 except for the rotating speed of the anode 142
and associated conditions. Here, the predetermined operation is an
operation that is set before acquiring of a fluoroscopic image of
the subject P is started. This operation may be a condition that is
set by the user, or it may be a preset fixed condition. However,
the rotating-speed control function 263 does not always determine
whether the derivation function 262 has finished deriving the
acquiring condition only on the basis of whether such an operation
is performed. Therefore, it is preferable that the rotating-speed
control function 263 uses this method in combination with the
method of using the statistic in the brightness of pixels of a
fluoroscopic image or other methods. For example, the
rotating-speed control function 263 determines that the derivation
function 262 has finished deriving the acquiring condition if the
user has performed the predetermined operation and if variations in
the statistic in the brightness of pixels of a fluoroscopic image
satisfy the determination condition.
[0063] The rotating-speed control function 263 may determine that
the derivation function 262 has finished deriving the acquiring
condition if a predetermined time has elapsed after the X-ray tube
14 has started to emit X-rays to acquire fluoroscopic images. This
is because, although the time it takes from the start of
fluoroscopy to derivation of the acquiring condition is not the
same during each examination, it is often nearly equal. Here, the
predetermined time is a time that is set before acquiring of
fluoroscopic images of the subject P is started. The time may be a
condition that is set by the user, or it may be a preset fixed
condition. The predetermined time, mentioned here, is for example 3
seconds. However, the rotating-speed control function 263 does not
always determine whether the derivation function 262 has finished
deriving the acquiring condition only on the basis of whether a
predetermined time has elapsed after fluoroscopy has been started.
Therefore, it is preferable that the rotating-speed control
function 263 uses this method in combination with the method of
using the statistic in the brightness of pixels of a fluoroscopic
image or other methods. For example, the rotating-speed control
function 263 determines that the derivation function 262 has
finished deriving the acquiring condition if a predetermined time
has elapsed after the X-ray tube 14 has started to emit X-rays to
acquire fluoroscopic images and if variations in the statistic in
the brightness of pixels of a fluoroscopic image satisfy the
determination condition.
[0064] The rotating-speed control function 263 may determine that
the derivation function 262 has finished deriving the acquiring
condition if the user satisfies the position condition. Here, the
position condition is set as, for example, an area where the user
can be located when acquiring of acquisition images is started. For
example, if the user stands within the area that is set as the
position condition, the rotating-speed control function 263
determines that the position condition is satisfied. Furthermore,
the rotating-speed control function 263 may acquire the position of
the user from images that are acquired by using for example an
optical camera. The position condition may be set on the basis of,
for example, the position where the user is often located when
acquiring of acquisition images is started during previous
examinations. Furthermore, the position condition may be a
condition that is set by the user, or it may be a preset condition
(a certain range from the console 20, or the like). Moreover, it is
preferable that the rotating-speed control function 263 uses this
method in combination with the method of using the statistic in the
brightness of pixels of a fluoroscopic image or other methods. For
example, the rotating-speed control function 263 determines that
the derivation function 262 has finished deriving the acquiring
condition if the user satisfies the position condition and if
variations in the statistic in the brightness of pixels of a
fluoroscopic image satisfy the determination condition.
[0065] As illustrated in FIG. 6, the processing circuitry 26 reads
the program, which corresponds to the rotating-speed control
function 263, from the memory circuitry 25 and executes it to
determine whether the rotating speed of the anode 142 in the
acquiring condition, derived at Step S12, is the high rotating
speed (Step S14). If the rotating speed of the anode 142 in the
acquiring condition, derived at Step S12, is the high rotating
speed (Yes at Step S14), the processing circuitry 26 proceeds to
the operation at Step S15. If the rotating speed of the anode 142
in the acquiring condition, derived at Step S12, is not the high
rotating speed (No at Step S14), the processing circuitry 26
proceeds to the operation at Step S17. That is, if the rotating
speed of the anode 142 in the acquiring condition, derived at Step
S12, is the low rotating speed, the processing circuitry 26
proceeds to the operation at Step S17. Furthermore, as illustrated
in FIG. 7, for example, the low rotating speed is 60 Hz, and the
high rotating speed is 180 Hz.
[0066] As illustrated in FIGS. 6 and 7, the processing circuitry 26
reads the program, which corresponds to the rotating-speed control
function 263, from the memory circuitry 25 and executes it to
increase the rotating speed of the anode 142 from the low rotating
speed to the high rotating speed (Step S15). Specifically, the
processing circuitry 26 uses the rotating-speed control function
263 to start to increase the rotating speed of the anode 142 from
the low rotating speed to the high rotating speed at the interval
from when the derivation function 262 finishes deriving the
acquiring condition to when the X-ray tube 14 finishes emitting
X-rays to acquire fluoroscopic images. For example, if the
operation at Step S14 is finished at a time T1, illustrated in FIG.
7, the processing circuitry 26 starts to increase the rotating
speed of the anode 142 from the low rotating speed to the high
rotating speed at the time T1. If the rotating speed of the anode
142 reaches the high rotating speed, the processing circuitry 26
proceeds to the operation at Step S16. For example, if the rotating
speed of the anode 142 reaches the high rotating speed at a time
T2, illustrated in FIG. 7, the processing circuitry 26 proceeds to
the operation at Step S16 at the time T2.
[0067] As illustrated in FIGS. 6 and 7, the processing circuitry 26
reads the program, which corresponds to the image-acquiring control
function 264, from the memory circuitry 25 and executes it to
acquire an acquisition image (Step S16). In this case, the rotating
speed of the anode 142 is 180 Hz. Specifically, the processing
circuitry 26 uses the image-acquiring control function 264 to start
image acquiring in the interval from when the rotating speed of the
anode 142, monitored by the monitoring function 261, reaches the
high rotating speed to when the time, which equals to the time
necessary to increase the low rotating speed to the high rotating
speed by the rotating-speed control function 263, elapses after the
starting point of reckoning, that is, after the X-ray tube 14
finishes emitting X-rays to acquire fluoroscopic images. For
example, as illustrated in FIG. 7, the processing circuitry 26
starts to acquire an acquisition image at the time T2 in which the
rotating speed of the anode 142 reaches the high rotating speed. If
acquiring of acquisition images is finished, the processing
circuitry 26 terminates the process.
[0068] As illustrated in FIG. 6, the processing circuitry 26 reads
the program, which corresponds to the image-acquiring control
function 264, from the memory circuitry 25 and executes it to
acquire an acquisition image (Step S17). In this case, the rotating
speed of the anode 142 is 60 Hz. If acquiring of acquisition images
is finished, the processing circuitry 26 terminates the
process.
[0069] An explanation is given above of a case where the rotating
speed of the anode 142 is started to increase to the high rotating
speed if it is determined that the acquiring condition has been
derived. Specifically, an explanation is given of a case where the
rotating speed of the anode 142 is started to increase if
variations in the statistic in the brightness of pixels of a
fluoroscopic image satisfy the determination condition, if the
operating mechanism is stopped, if the information indicating that
the subject P has stopped breathing or the information indicating
that the subject P has received a command to stop breathing is
received, if the information indicating that the subject P has
stopped moving or the information indicating that the subject P has
received a command to stop moving is received, if the user has
performed a predetermined operation, if a predetermined time has
elapsed after the X-ray tube 14 has started to emit X-rays to
acquire fluoroscopic images, or if the user satisfies the position
condition. However, this is not a limitation on the embodiment.
[0070] For example, there may be a case where the processing
circuitry 26 determines the time in which the rotating speed of the
anode 142 is started to increase by using the state information
that indicates the state of examination and starts to increase the
rotating speed of the anode 142 at the determined time. Here, the
state information is at least one of for example the information
that indicates variations in the statistic in the brightness of
pixels of a fluoroscopic image, the information that indicates
whether the operating mechanism is stopped, the information that
indicates whether the subject has stopped breathing, the
information that indicates whether the subject has received a
command to stop breathing, the information that indicates whether
the subject has stopped moving, the information that indicates
whether the subject has received a command to stop moving, the
information that indicates whether the user has performed a
predetermined operation, the information that indicates the time
that has elapsed after the X-ray tube 14 has started to emit X-rays
to acquire fluoroscopic images, and the information that indicates
the position of the user.
[0071] An explanation is given below of an example of the process
by the processing circuitry 26 to determine the time when the
rotating speed of the anode 142 is started to increase by using the
state information. First, the processing circuitry 26 acquires the
combination of the state information at the time when the rotating
speed of the anode 142 is started to increase and the evaluation of
the time when the rotating speed of the anode 142 is started to
increase. Here, the processing circuitry 26 acquires this
combination each time an examination is conducted.
[0072] The state information at the time when the rotating speed of
the anode 142 is started to increase is, for example, the
information that indicates variations in the statistic in the
brightness of pixels of a fluoroscopic image (e.g., a differential
value of standard deviation in brightness) at the time when the
rotating speed of the anode 142 is started to increase.
Furthermore, for example, the state information at the time when
the rotating speed of the anode 142 is started to increase is the
information that indicates whether the operating mechanism is
stopped, whether the subject has stopped breathing, whether the
subject has received a command to stop breathing, whether the
subject has stopped moving, whether the subject has received a
command to stop moving, whether the user has performed a
predetermined operation, whether a predetermined time has elapsed
after the X-ray tube 14 has started to emit X-rays to acquire
fluoroscopic images, whether the user satisfies the position
condition, or the like, at the time when the rotating speed of the
anode 142 is started to increase.
[0073] Furthermore, the evaluation of the time when the rotating
speed of the anode 142 is started to increase is an evaluation that
indicates how appropriate the time when the rotating speed of the
anode 142 is started to increase is in terms of prompt start of
acquiring of acquisition images. Hereafter, the evaluation of the
time when the rotating speed of the anode 142 is started to
increase is sometimes simply referred to as the evaluation. For
example, the processing circuitry 26 acquires, as an evaluation,
the difference between the time when the rotating speed of the
anode 142 reaches the high rotating speed and the start time of
image acquiring. For example, the processing circuitry 26 acquires
the difference between the time when the rotating speed of the
anode 142 reaches the high rotating speed and the start time of
image acquiring, which is the time when the user performs an input
operation indicating the start of image acquiring via the input
circuitry 21.
[0074] For example, if the user performs an input operation
indicating the start of image acquiring before the rotating speed
of the anode 142 reaches the high rotating speed, the processing
circuitry 26 may make the evaluation that the time when the
rotating speed of the anode 142 is started to increase is too late.
This is because, in this case, it may be estimated that if the
rotating speed of the anode 142 is started to increase earlier,
acquiring of an acquisition image may be started more promptly.
Furthermore, for example, if it takes a long time from when the
rotating speed of the anode 142 reaches the high rotating speed to
when image acquiring is started, the processing circuitry 26 may
make the evaluation that the time when the rotating speed of the
anode 142 is started to increase is too early. This is because, in
this case, it may be estimated that even if the time when the
rotating speed of the anode 142 is started to increase is delayed
more, the start time of acquiring of acquisition images is not
affected. Therefore, the processing circuitry 26 acquires the
evaluation that it is more appropriate as the time when the
rotating speed of the anode 142 is started to increase if the
difference between the time when the rotating speed of the anode
142 reaches the high rotating speed and the start time of image
acquiring is smaller.
[0075] Next, the processing circuitry 26 calculates the weighting
coefficient for each piece of state information on the basis of the
acquired evaluation. For example, the processing circuitry 26
acquires the combination of the state information at the time when
the rotating speed of the anode 142 is started to increase and the
evaluation with regard to multiple examinations, and it compares
the acquired combinations with each other to acquire the degree of
correlation between each piece of state information and an
evaluation. For example, the processing circuitry 26 acquires, as
the degree of correlation, the correlation coefficient between the
variation in the statistic in the brightness of pixels of a
fluoroscopic image at the time when the rotating speed of the anode
142 is started to increase and the evaluation. Furthermore, for
example, the processing circuitry 26 acquires, as the degree of
correlation, the difference between the average value of
evaluations in a case where the operating mechanism is stopped at
the time when the rotating speed of the anode 142 is started to
increase and the average value of evaluations in a case where the
operating mechanism is not stopped at the time when the rotating
speed of the anode 142 is started to increase. Then, for each piece
of state information, the processing circuitry 26 calculates the
weighting coefficient for each piece of state information in
accordance with the degree of correlation with the evaluation.
[0076] Here, an explanation is given of a case where an examination
E1 is further conducted after a weighting coefficient is calculated
for each piece of state information. The processing circuitry 26
determines the time when the rotating speed of the anode 142 is
started to increase during the examination E1 on the basis of the
state information indicating the state of the examination E1 and
the weighting coefficient. Specifically, the processing circuitry
26 receives an input of the state information, which indicates
variations in the statistic in the brightness of pixels of a
fluoroscopic image or whether the operating mechanism is stopped,
in real time and performs calculations on the input state
information by using the weighting coefficient, thereby determining
the time when the rotating speed of the anode 142 is started to
increase. Then, the processing circuitry 26 starts to increase the
rotating speed of the anode 142 at the determined time.
[0077] Here, the processing circuitry 26 further acquires the
evaluation of the time when the rotating speed of the anode 142 is
started to increase during the examination E1. Furthermore, the
processing circuitry 26 uses the acquired evaluation and the state
information, which indicates the state of the examination E1 at the
time when the rotating speed of the anode 142 starts to increase,
to change the weighting coefficient for each piece of state
information. In other words, each time an examination is conducted,
the processing circuitry 26 learns the weighting coefficient for
each piece of state information in the relationship between the
state information at the time when the rotating speed of the anode
142 is started to increase and the evaluation of the time when the
rotating speed of the anode 142 is started to increase.
Furthermore, if an examination is further conducted, the processing
circuitry 26 may determine the time when the rotating speed of the
anode 142 is started to increase on the basis of the state
information in the examination and the learnt weighting coefficient
and start to increase the rotating speed of the anode 142 at the
determined time.
[0078] The X-ray diagnostic apparatus 1 according to the first
embodiment is explained above. In accordance with the derived
acquiring condition, the rotating-speed control function 263 starts
to increase the rotating speed of the anode 142 from the low
rotating speed to the high rotating speed before the X-ray tube 14
finishes emitting X-rays to acquire fluoroscopic images. Then, the
image-acquiring control function 264 starts to acquire acquisition
images in the interval from when the rotating speed of the anode
142 reaches the high rotating speed to when the time necessary to
increase the low rotating speed to the high rotating speed elapses
after the X-ray tube 14 finishes emitting X-rays to acquire
fluoroscopic images.
[0079] Conversely, as illustrated in FIG. 8, the conventional X-ray
diagnostic apparatus starts to increase the rotating speed of the
anode 142 from the low rotating speed to the high rotating speed at
a time t1 in which the X-ray tube finishes emitting X-rays to
acquire fluoroscopic images. Then, as illustrated in FIG. 8, the
conventional X-ray diagnostic apparatus starts to acquire
acquisition images after a time t2 in which the time necessary to
increase the low rotating speed to the high rotating speed elapses
after the X-ray tube finishes emitting X-rays to acquire
fluoroscopic images.
[0080] That is, the X-ray diagnostic apparatus 1 according to the
first embodiment may start to acquire acquisition images more
promptly than the conventional X-ray diagnostic apparatus.
[0081] Furthermore, if the processing circuitry 26 does not derive
an acquiring condition from a fluoroscopic image at Step S12, the
condition for acquiring acquisition images by the X-ray diagnostic
apparatus 1 is previously set. In this case, if a predetermined
time has elapsed after acquiring of fluoroscopic images has been
started, the processing circuitry 26 does not perform the
operations at Step S13 and Step S14, and it proceeds to the
operation at Step S15 or Step S17 in accordance with the previously
set condition.
[0082] The X-ray diagnostic apparatus 1 according to the first
embodiment does not acquire acquisition images from when the
derivation function 262 finishes deriving the acquiring condition
to when the rotating speed of the anode 142, monitored by the
monitoring function 261, reaches the high rotating speed.
Conversely, an X-ray diagnostic apparatus according to the second
embodiment acquires acquisition images from when the derivation
function 262 finishes deriving the acquiring condition to when the
rotating speed of the anode 142, monitored by the monitoring
function 261, reaches the high rotating speed. Here, the same
reference numerals as those used in the explanation of the first
embodiment are used in the explanation of the second embodiment,
and duplicated explanations are appropriately omitted.
[0083] With reference to FIGS. 9 and 10, an explanation is given of
the process that is performed by the X-ray diagnostic apparatus 1
according to the second embodiment. FIG. 9 is a flowchart that
illustrates an example of the process that is performed by the
X-ray diagnostic apparatus according to the second embodiment. FIG.
10 is a diagram that illustrates an example of the case where the
X-ray diagnostic apparatus according to the second embodiment
acquires a fluoroscopic image and then increases the rotating speed
of the anode from the low rotating speed to the high rotating speed
while it acquires an acquisition image.
[0084] While the X-ray diagnostic apparatus 1 is in operation, the
processing circuitry 26 reads the program, which corresponds to the
monitoring function 261, from the memory circuitry 25 and executes
it to receive the rotating speed of the anode 142 from the
rotating-speed monitoring device 145.
[0085] As illustrated in FIGS. 9 and 10, the processing circuitry
26 reads the program, which corresponds to the rotating-speed
control function 263, from the memory circuitry 25 and executes it
to start to increase the rotating speed of the anode 142 (Step
S21). For example, as illustrated in FIGS. 9 and 10, the processing
circuitry 26 derives an acquiring condition from the fluoroscopic
image and then starts to increase the rotating speed of the anode
142 from the low rotating speed to the high rotating speed.
[0086] As illustrated in FIG. 9, the processing circuitry 26 reads
the program, which corresponds to the derivation function 262, from
the memory circuitry 25 and executes it to derive an irradiation
possible condition (Step S22). The irradiation possible condition
is for example the condition for acquisition image acquiring that
may be achieved by using the rotating speed of the anode 142 that
is monitored by the monitoring function 261 at present. The
irradiation possible condition is, for example, the tube current,
the tube voltage, the current that flows through the cathode 141,
the electric potential of the grid 143, the positions of the
aperture blades of the collimator 15, the position of the tabletop
of the couch 13, or the arrangement of the C arm 18.
[0087] As illustrated in FIG. 9, the processing circuitry 26 reads
the program, which corresponds to the image-acquiring control
function 264, from the memory circuitry 25 and executes it to
determine whether the acquiring condition, derived from the
fluoroscopic image, falls within the irradiation possible condition
(Step S23). Specifically, the processing circuitry 26 uses the
image-acquiring control function 264 to determine whether the X-ray
diagnostic apparatus 1 may conduct acquiring of acquisition images
under the acquiring condition, derived from the fluoroscopic image,
by using the current rotating speed of the anode 142. If the
acquiring condition, derived from the fluoroscopic image, falls
within the irradiation possible condition (Yes at Step S23), the
processing circuitry 26 proceeds to the operation at Step S24. If
the acquiring condition, derived from the fluoroscopic image, does
not fall within the irradiation possible condition (No at Step
S23), the processing circuitry 26 proceeds to the operation at Step
S25. Furthermore, the acquiring condition mentioned here is the
acquiring condition that is explained in the first embodiment.
[0088] As illustrated in FIGS. 9 and 10, the processing circuitry
26 reads the program, which corresponds to the image-acquiring
control function 264, from the memory circuitry 25 and executes it
to acquire an acquisition image under the acquiring condition that
is derived from the fluoroscopic image (Step S24). If acquiring of
the acquisition image is finished, the processing circuitry 26
terminates the process.
[0089] As illustrated in FIGS. 9 and 10, the processing circuitry
26 reads the program, which corresponds to the image-acquiring
control function 264, from the memory circuitry 25 and executes it
to acquire an acquisition image under the irradiation possible
condition (Step S25). If acquiring of the acquisition image is
finished, the processing circuitry 26 proceeds to the operation at
Step S26.
[0090] As illustrated in FIG. 9, the processing circuitry 26 reads
the program, which corresponds to the rotating-speed control
function 263, and executes it to determine whether the current
rotating speed of the anode 142 is higher than the rotating speed
of the anode 142 at Step S22 (Step S26). If the current rotating
speed of the anode 142 is higher than the rotating speed of the
anode 142 at Step S22 (Yes at Step S26), the processing circuitry
26 proceeds to the operation at Step S22. If the current rotating
speed of the anode 142 is the same as the rotating speed of the
anode 142 at Step S22 (No at Step S26), the processing circuitry 26
terminates the process. Furthermore, in this case, the rotating
speed of the anode 142 has reached the high rotating speed.
[0091] The X-ray diagnostic apparatus 1 according to the second
embodiment has been explained above. The derivation function 262
derives the irradiation possible condition that may be achieved by
using the rotating speed of the anode 142 that is monitored by the
monitoring function 261. If the acquiring condition does not fall
within the irradiation possible condition, the image-acquiring
control function 264 acquires acquisition images under the
irradiation possible condition. Therefore, the X-ray diagnostic
apparatus 1 may starts to acquire acquisition images before the
rotating speed of the anode 142, monitored by the monitoring
function 261, reaches the high rotating speed.
[0092] Conversely, as illustrated in FIG. 8, the conventional X-ray
diagnostic apparatus does not acquire acquisition images from the
time t1, at which the X-ray tube finishes emitting X-rays to
acquire fluoroscopic images, to the time t2, at which the rotating
speed of the anode 142 reaches the high rotating speed. Therefore,
as illustrated in FIG. 8, the conventional X-ray diagnostic
apparatus may starts to acquire acquisition images only after the
time t2 at which the rotating speed of the anode reaches the high
rotating speed.
[0093] That is, the X-ray diagnostic apparatus 1 according to the
second embodiment may starts to acquire acquisition images promptly
as compared to conventional X-ray diagnostic apparatuses.
[0094] An explanation is given of a case where, after a
fluoroscopic image is acquired, the rotating speed of the anode 142
is started to increase and simultaneously an acquisition image is
acquired under the irradiation possible condition; however, this is
not a limitation on the embodiment. As illustrated in FIG. 11, for
example, the X-ray diagnostic apparatus 1 according to the second
embodiment may acquire acquisition images under the irradiation
possible condition if the acquiring condition, derived from the
fluoroscopic image, does not fall within the irradiation possible
condition from a time t1 when the rotating speed of the anode 142
is started to increase from the stopped state to the high rotating
speed until a time t2 when the rotating speed of the anode 142
reaches the high rotating speed.
[0095] Alternatively, for example, the X-ray diagnostic apparatus 1
according to the second embodiment may acquire acquisition images
under the irradiation possible condition if the acquiring
condition, derived from the fluoroscopic image, does not fall
within the irradiation possible condition from the time when the
rotating speed of the anode 142 starts to increase from the stopped
state to the low rotating speed until the time when the rotating
speed of the anode 142 reaches the high rotating speed.
[0096] In these cases, the X-ray diagnostic apparatus 1 performs
the same process as that is explained with reference to FIG. 9.
However, in these cases, the acquiring condition is previously set,
and the processing circuitry 26 starts to increase the rotating
speed of the anode 142 from the stopped state to the high rotating
speed at Step S21. Therefore, the X-ray diagnostic apparatus 1 may
start to acquire acquisition images even before the rotating speed
of the anode 142, monitored by the monitoring function 261, reaches
the high rotating speed.
[0097] Conversely, as illustrated in FIG. 12, the conventional
X-ray diagnostic apparatus does not acquire acquisition images from
the time t1 when the rotating speed of the anode is started to
increase from the stopped state to the high rotating speed until
the time t2 when the rotating speed of the anode reaches the high
rotating speed. Therefore, as illustrated in FIG. 12, the
conventional X-ray diagnostic apparatus may start to acquire
acquisition images only after the time t2 when the rotating speed
of the anode reaches the high rotating speed.
[0098] That is, the X-ray diagnostic apparatus 1 according to the
second embodiment may start to acquire acquisition images promptly
as compared to conventional X-ray diagnostic apparatuses even in a
case where the rotating speed of the anode 142 is increased from
the stopped state to the high rotating speed.
[0099] An X-ray diagnostic apparatus according to a third
embodiment decreases the rotating speed of the anode if the
rotating speed of the anode, monitored by the monitoring function,
is a rotating speed at which the anode resonates. Furthermore, the
same reference numerals as those used in the explanations of the
first embodiment and the second embodiment are used in the
explanation of the third embodiment, and duplicated explanations
are omitted as appropriate.
[0100] With reference to FIG. 13, the X-ray diagnostic apparatus 1
according to the third embodiment is explained. FIG. 13 is a
diagram that illustrates an example of the case where the X-ray
diagnostic apparatus according to the third embodiment applies a
brake to the anode while the rotating speed of the anode is
decreased from the high rotating speed to the stopped state.
[0101] As illustrated in FIG. 13, the X-ray diagnostic apparatus 1
increases the rotating speed of the anode 142 from the stopped
state to the high rotating speed during the time T(S), acquires an
acquisition image, and decreases the rotating speed of the anode
142 from the high rotating speed to the stopped state. As
illustrated in FIG. 13, the processing circuitry 26 performs the
following operation when the rotating speed of the anode 142 is
decreased from the high rotating speed to the stopped state.
[0102] While the X-ray diagnostic apparatus 1 is in operation, the
processing circuitry 26 reads the program, which corresponds to the
monitoring function 261, from the memory circuitry 25 and executes
it to receive the rotating speed of the anode 142 from the
rotating-speed monitoring device 145. The processing circuitry 26
reads the program, which corresponds to the rotating-speed control
function 263, from the memory circuitry 25 and executes it to
decrease the rotating speed of the anode 142 if the rotating speed
of the anode 142, monitored by the monitoring function 261, is a
rotating speed at which the anode 142 resonates.
[0103] Specifically, if the rotating speed of the anode 142,
monitored by the monitoring function 261, is a rotating speed at
which the anode 142 resonates, the processing circuitry 26 applies
a brake to the rotation of the anode 142. The processing circuitry
26 uses the rotating-speed control function 263 to control the
anode drive circuitry 16 so as to control the current that flows
through the coil, which generates the rotating magnetic field,
thereby applying a brake to the rotation of the anode 142. This
allows the processing circuitry 26 to shorten the time during which
the rotating speed of the anode 142 is the rotating speed at which
the anode resonates, as indicated by the area A in FIG. 13.
[0104] The X-ray diagnostic apparatus 1 according to the third
embodiment decreases the rotating speed of the anode 142 if the
rotating speed of the anode 142, monitored by the monitoring
function 261, is a rotating speed at which the anode 142 resonates.
Therefore, the X-ray diagnostic apparatus 1 may reduce the energy
that is necessary to apply a brake to the anode 142.
[0105] Furthermore, the processing circuitry 26 does not apply a
brake to the rotation of the anode 142 if the rotating speed of the
anode 142, monitored by the monitoring function 261, is not a
rotating speed at which the anode 142 resonates. Specifically, if
the rotating speed of the anode 142, monitored by the monitoring
function 261, is not a rotating speed at which the anode 142
resonates, the processing circuitry 26 rotates the anode 142
through inertia during a time that is longer than the time T(E),
which is illustrated in FIG. 13.
[0106] Thus, the X-ray diagnostic apparatus 1 according to the
third embodiment may cause the rotating speed of the anode 142 to
promptly reach the rotating speed at which acquisition images can
be acquired again and may promptly start to acquiring acquisition
images. Here, the rotating speed at which acquisition images can be
acquired is for example the high rotating speed or the low rotating
speed. Alternatively, the X-ray diagnostic apparatus 1 may cause
the rotating speed of the anode 142 to promptly reach the rotating
speed at which fluoroscopic images can be acquired again and may
promptly start to acquire fluoroscopic images. Here, the rotating
speed at which fluoroscopic images can be acquired is for example
the low rotating speed. Furthermore, the X-ray diagnostic apparatus
1 may prevent the coil, which applies a brake to the anode 142, and
the anode drive circuitry 16 from being heated more than
necessary.
[0107] Although the first to third embodiments have been explained
above, various different embodiments may be implemented other than
the above-described embodiments.
[0108] In the above-described embodiments, the X-ray diagnostic
apparatus 1 is explained. That is, an explanation is given of a
case where the processing circuitry 26, included in the X-ray
diagnostic apparatus 1, derives the acquiring condition from a
fluoroscopic image and starts to increase the rotating speed of the
anode 142 in accordance with the derived acquiring condition.
However, this is not a limitation on the embodiment. For example,
there may be a case where a medical-information processing
apparatus, which is connected to the X-ray diagnostic apparatus 1,
calculates the time when the rotating speed of the anode 142 is
started to increase in the X-ray diagnostic apparatus 1 and
notifies the calculated time to the X-ray diagnostic apparatus
1.
[0109] For example, the medical-information processing apparatus,
which is connected to the X-ray diagnostic apparatus 1, first
acquires the acquiring condition based on a fluoroscopic image. For
example, the medical-information processing apparatus acquires
fluoroscopic images, which are acquired by the X-ray diagnostic
apparatus 1, via a network, or the like, and derives an acquiring
condition from the acquired fluoroscopic images. Furthermore,
according to another example, the X-ray diagnostic apparatus 1
derives an acquiring condition from the acquired fluoroscopic
images, and the medical-information processing apparatus acquires
the acquiring condition, derived by the X-ray diagnostic apparatus
1, via a network, or the like.
[0110] Next, the medical-information processing apparatus
calculates the time when the rotating speed of the anode 142 in the
X-ray diagnostic apparatus 1 is started to increase from the low
rotating speed to the high rotating speed in accordance with the
acquired acquiring condition, and it notifies the calculated time
to the X-ray diagnostic apparatus 1.
[0111] For example, the medical-information processing apparatus
acquires fluoroscopic images, acquired by the X-ray diagnostic
apparatus 1, in real time and notifies the X-ray diagnostic
apparatus 1 of the time when variations in the statistic in the
brightness of pixels of the fluoroscopic image satisfy the
determination condition as the time when the rotating speed of the
anode 142 is started to increase. Furthermore, for example, the
medical-information processing apparatus notifies the X-ray
diagnostic apparatus 1 of, as the time when the rotating speed of
the anode 142 is started to increase, the time when variations in
the statistic in the brightness of pixels of the fluoroscopic image
satisfy the determination condition and when at least one of the
following conditions is satisfied: the operating mechanism is
stopped, the subject P has stopped breathing, the subject P has
received a command to stop breathing, the subject P has stopped
moving, the subject P has received a command to stop moving, the
user has performed a predetermined operation, a predetermined time
has elapsed after the X-ray tube 14 has started to emit X-rays to
acquire fluoroscopic images, and the user satisfies the position
condition. Then, after receiving the notification, the X-ray
diagnostic apparatus 1 starts to increase the rotating speed of the
anode 142 to the high rotating speed at the notified time.
Furthermore, if the notified time is the current time or the past
time, the X-ray diagnostic apparatus 1 starts to increase the
rotating speed of the anode 142 as soon as a notification is
received.
[0112] Furthermore, for example, the medical-information processing
apparatus calculates the time when the rotating speed of the anode
142 is started to increase on the basis of the state information
during an examination and the learned weighting coefficient and
notifies the X-ray diagnostic apparatus 1 of the calculated time as
the time when the rotating speed of the anode 142 is started to
increase. Then, after receiving a notification, the X-ray
diagnostic apparatus 1 starts to increase the rotating speed of the
anode 142 from the low rotating speed to the high rotating
speed.
[0113] Here, there may be a case where the medical-information
processing apparatus is connected to multiple X-ray diagnostic
apparatuses. In such a case, the medical-information processing
apparatus calculates and notifies the time when the rotating speed
of the anode is started to increase with regard to each X-ray
diagnostic apparatus. Furthermore, the medical-information
processing apparatus acquires, from each X-ray diagnostic
apparatus, the state information at the time when the rotating
speed of the anode starts to increase and the evaluation of the
time when the rotating speed of the anode is started to increase,
and it learns the weighting coefficient with regard to each piece
of state information.
[0114] Specifically, the medical-information processing apparatus,
connected to multiple X-ray diagnostic apparatuses, acquires the
state information at the time when the rotating speed of the anode
is started to increase and the evaluation of the time when the
rotating speed of the anode is started to increase each time the
rotating speed of the anode increases from the low rotating speed
to the high rotating speed with regard to each X-ray diagnostic
apparatus. In other words, the medical-information processing
apparatus, connected to multiple X-ray diagnostic apparatuses,
acquires the combination of the state information and the
evaluation during each examination. Then, the medical-information
processing apparatus updates the weighting coefficient with regard
to each piece of state information on the basis of the acquired
combination. Specifically, the medical-information processing
apparatus learns the weighting coefficient with regard to each
piece of state information during each examination that uses any of
the connected X-ray diagnostic apparatuses. Thus, the
medical-information processing apparatus, connected to multiple
X-ray diagnostic apparatuses, may correctly calculate the time when
the rotating speed of the anode is started to increase by using the
weighting coefficient that is learned by using lots of data as
compared to the case where it is connected to only the X-ray
diagnostic apparatus 1.
[0115] Furthermore, there may be a case where the
medical-information processing apparatus learns the weighting
coefficient for each piece of state information with regard to each
user. Furthermore, there may be a case where, if the
medical-information processing apparatus is connected to multiple
X-ray diagnostic apparatuses, which are provided in multiple sites
(e.g., multiple hospitals), it learns the weighting coefficient for
each piece of state information with regard to each site.
[0116] The above-described embodiments may be used in combination
as appropriate.
[0117] The above-described processor is for example a central
processing unit (CPU), a graphics processing unit (GPU), an
application specific integrated circuit (ASIC), a programmable
logic device (PLD), or a field programmable gate array (FPGA).
Furthermore, the programmable logic device (PLD) is for example a
simple programmable logic device (SPLD) or a complex programmable
logic device (CPLD).
[0118] According to the above-described embodiment, the
high-voltage generation circuitry 11, the collimator adjustment
circuitry 12, the anode drive circuitry 16, the drive circuitry 19,
the generation circuitry 23, and the processing circuitry 26 read
and execute programs, stored in the memory circuitry 25, to
implement their functions; however, this is not a limitation.
Instead of storing the programs in the memory circuitry 25, the
program may be directly installed in each of the circuitry. In this
case, the circuitry reads and executes the directly installed
programs to implement the functions.
[0119] Each of the circuitry, illustrated in FIG. 1, may be
separated or combined as appropriate. For example, the processing
circuitry 26 may be separated into image-acquiring control
circuitry and control circuitry that implement each function, i.e.,
the monitoring function 261, the derivation function 262, the
rotating-speed control function 263, the image-acquiring control
function 264, and the control function 265. Furthermore, for
example, the high-voltage generation circuitry 11, the collimator
adjustment circuitry 12, the anode drive circuitry 16, the drive
circuitry 19, the generation circuitry 23, and the processing
circuitry 26 may be arbitrarily combined.
[0120] According to at least one of the above-described
embodiments, it is possible to provide the X-ray diagnostic
apparatus that may promptly start to acquire acquisition
images.
[0121] While certain embodiments have been described, these
embodiments have been presented by way of example only, and are not
intended to limit the scope of the inventions. Indeed, the novel
embodiments described herein may be embodied in a variety of other
forms; furthermore, various omissions, substitutions and changes in
the form of the embodiments described herein may be made without
departing from the spirit of the inventions. The accompanying
claims and their equivalents are intended to cover such forms or
modifications as would fall within the scope and spirit of the
inventions.
* * * * *